1. Field of the Invention
This invention relates to a fuel metering control system for an internal combustion engine.
2. Description of the Related Art
It is known in the art to conduct a fuel metering feedback control such that the air/fuel ratio at the exhaust confluence point of a multicylinder internal combustion engine converges to a desired value using an output of an air/fuel ratio sensor installed there. Moreover, there has been proposed a technique to conduct both the exhaust confluence point air/fuel ratio feedback control and the individual cylinder air/fuel ratio feedback control, as taught, for example, by Japanese Patent Publication No. Sho 62(1987)-20,365.
However, the aforesaid prior art system was not able to effectively decrease variance between individual cylinder air/fuel ratios, since it did not take into account the fuel transport delay caused by fuel adhering to the wall of the intake manifold. As a result, the prior art system was disadvantageous in that it could not enlarge the margin of air/fuel ratio leaning or canister purging.